/*
 * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.sun.org.apache.xml.internal.dtm;

import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xml.internal.utils.XMLStringFactory;

/**
 * A DTMManager instance can be used to create DTM and
 * DTMIterator objects, and manage the DTM objects in the system.
 *
 * <p>The system property that determines which Factory implementation
 * to create is named "com.sun.org.apache.xml.internal.utils.DTMFactory". This
 * property names a concrete subclass of the DTMFactory abstract
 * class. If the property is not defined, a platform default is be used.</p>
 *
 * <p>An instance of this class <emph>must</emph> be safe to use across
 * thread instances.  It is expected that a client will create a single instance
 * of a DTMManager to use across multiple threads.  This will allow sharing
 * of DTMs across multiple processes.</p>
 *
 * <p>Note: this class is incomplete right now.  It will be pretty much
 * modeled after javax.xml.transform.TransformerFactory in terms of its
 * factory support.</p>
 *
 * <p>State: In progress!!</p>
 */
public abstract class DTMManager {

    /**
     * Factory for creating XMLString objects.
     * %TBD% Make this set by the caller.
     */
    protected XMLStringFactory m_xsf = null;

    private boolean _overrideDefaultParser;

    /**
     * Default constructor is protected on purpose.
     */
    protected DTMManager() {
    }

    /**
     * Get the XMLStringFactory used for the DTMs.
     *
     * @return a valid XMLStringFactory object, or null if it hasn't been set yet.
     */
    public XMLStringFactory getXMLStringFactory() {
        return m_xsf;
    }

    /**
     * Set the XMLStringFactory used for the DTMs.
     *
     * @param xsf a valid XMLStringFactory object, should not be null.
     */
    public void setXMLStringFactory(XMLStringFactory xsf) {
        m_xsf = xsf;
    }

    /**
     * Obtain a new instance of a <code>DTMManager</code>.
     * This static method creates a new factory instance
     * using the default <code>DTMManager</code> implementation, which is
     * <code>com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault</code>.
     * </li>
     * </ul>
     * <p>
     * Once an application has obtained a reference to a <code>
     * DTMManager</code> it can use the factory to configure
     * and obtain parser instances.
     *
     * @return new DTMManager instance, never null.
     * @throws DTMException if the implementation is not available or cannot be instantiated.
     */
    public static DTMManager newInstance(XMLStringFactory xsf)
            throws DTMException {
        final DTMManager factoryImpl = new com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault();
        factoryImpl.setXMLStringFactory(xsf);

        return factoryImpl;
    }

    /**
     * Get an instance of a DTM, loaded with the content from the
     * specified source.  If the unique flag is true, a new instance will
     * always be returned.  Otherwise it is up to the DTMManager to return a
     * new instance or an instance that it already created and may be being used
     * by someone else.
     * <p>
     * (More parameters may eventually need to be added for error handling
     * and entity resolution, and to better control selection of implementations.)
     *
     * @param source           the specification of the source object, which may be null,
     *                         in which case it is assumed that node construction will take
     *                         by some other means.
     * @param unique           true if the returned DTM must be unique, probably because it
     *                         is going to be mutated.
     * @param whiteSpaceFilter Enables filtering of whitespace nodes, and may
     *                         be null.
     * @param incremental      true if the DTM should be built incrementally, if
     *                         possible.
     * @param doIndexing       true if the caller considers it worth it to use
     *                         indexing schemes.
     * @return a non-null DTM reference.
     */
    public abstract DTM getDTM(javax.xml.transform.Source source,
                               boolean unique, DTMWSFilter whiteSpaceFilter,
                               boolean incremental, boolean doIndexing);

    /**
     * Get the instance of DTM that "owns" a node handle.
     *
     * @param nodeHandle the nodeHandle.
     * @return a non-null DTM reference.
     */
    public abstract DTM getDTM(int nodeHandle);

    /**
     * Given a W3C DOM node, try and return a DTM handle.
     * Note: calling this may be non-optimal.
     *
     * @param node Non-null reference to a DOM node.
     * @return a valid DTM handle.
     */
    public abstract int getDTMHandleFromNode(org.w3c.dom.Node node);

    /**
     * Creates a DTM representing an empty <code>DocumentFragment</code> object.
     *
     * @return a non-null DTM reference.
     */
    public abstract DTM createDocumentFragment();

    /**
     * Release a DTM either to a lru pool, or completely remove reference.
     * DTMs without system IDs are always hard deleted.
     * State: experimental.
     *
     * @param dtm              The DTM to be released.
     * @param shouldHardDelete True if the DTM should be removed no matter what.
     * @return true if the DTM was removed, false if it was put back in a lru pool.
     */
    public abstract boolean release(DTM dtm, boolean shouldHardDelete);

    /**
     * Create a new <code>DTMIterator</code> based on an XPath
     * <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a> or
     * a <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>.
     *
     * @param xpathCompiler ??? Somehow we need to pass in a subpart of the
     *                      expression.  I hate to do this with strings, since the larger expression
     *                      has already been parsed.
     * @param pos           The position in the expression.
     * @return The newly created <code>DTMIterator</code>.
     */
    public abstract DTMIterator createDTMIterator(Object xpathCompiler,
                                                  int pos);

    /**
     * Create a new <code>DTMIterator</code> based on an XPath
     * <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a> or
     * a <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>.
     *
     * @param xpathString Must be a valid string expressing a
     *                    <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a> or
     *                    a <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>.
     * @param presolver   An object that can resolve prefixes to namespace URLs.
     * @return The newly created <code>DTMIterator</code>.
     */
    public abstract DTMIterator createDTMIterator(String xpathString,
                                                  PrefixResolver presolver);

    /**
     * Create a new <code>DTMIterator</code> based only on a whatToShow
     * and a DTMFilter.  The traversal semantics are defined as the
     * descendant access.
     * <p>
     * Note that DTMIterators may not be an exact match to DOM
     * NodeIterators. They are initialized and used in much the same way
     * as a NodeIterator, but their response to document mutation is not
     * currently defined.
     *
     * @param whatToShow               This flag specifies which node types may appear in
     *                                 the logical view of the tree presented by the iterator. See the
     *                                 description of <code>NodeFilter</code> for the set of possible
     *                                 <code>SHOW_</code> values.These flags can be combined using
     *                                 <code>OR</code>.
     * @param filter                   The <code>NodeFilter</code> to be used with this
     *                                 <code>DTMFilter</code>, or <code>null</code> to indicate no filter.
     * @param entityReferenceExpansion The value of this flag determines
     *                                 whether entity reference nodes are expanded.
     * @return The newly created <code>DTMIterator</code>.
     */
    public abstract DTMIterator createDTMIterator(int whatToShow,
                                                  DTMFilter filter, boolean entityReferenceExpansion);

    /**
     * Create a new <code>DTMIterator</code> that holds exactly one node.
     *
     * @param node The node handle that the DTMIterator will iterate to.
     * @return The newly created <code>DTMIterator</code>.
     */
    public abstract DTMIterator createDTMIterator(int node);

    /* Flag indicating whether an incremental transform is desired */
    public boolean m_incremental = false;

    /*
     * Flag set by FEATURE_SOURCE_LOCATION.
     * This feature specifies whether the transformation phase should
     * keep track of line and column numbers for the input source
     * document.
     */
    public boolean m_source_location = false;

    /**
     * Get a flag indicating whether an incremental transform is desired
     *
     * @return incremental boolean.
     */
    public boolean getIncremental() {
        return m_incremental;
    }

    /**
     * Set a flag indicating whether an incremental transform is desired
     * This flag should have the same value as the FEATURE_INCREMENTAL feature
     * which is set by the TransformerFactory.setAttribut() method before a
     * DTMManager is created
     *
     * @param incremental boolean to use to set m_incremental.
     */
    public void setIncremental(boolean incremental) {
        m_incremental = incremental;
    }

    /**
     * Get a flag indicating whether the transformation phase should
     * keep track of line and column numbers for the input source
     * document.
     *
     * @return source location boolean
     */
    public boolean getSource_location() {
        return m_source_location;
    }

    /**
     * Set a flag indicating whether the transformation phase should
     * keep track of line and column numbers for the input source
     * document.
     * This flag should have the same value as the FEATURE_SOURCE_LOCATION feature
     * which is set by the TransformerFactory.setAttribut() method before a
     * DTMManager is created
     *
     * @param sourceLocation boolean to use to set m_source_location
     */
    public void setSource_location(boolean sourceLocation) {
        m_source_location = sourceLocation;
    }

    /**
     * Return the state of the services mechanism feature.
     */
    public boolean overrideDefaultParser() {
        return _overrideDefaultParser;
    }

    /**
     * Set the state of the services mechanism feature.
     */
    public void setOverrideDefaultParser(boolean flag) {
        _overrideDefaultParser = flag;
    }

    // -------------------- private methods --------------------

    /**
     * This value, set at compile time, controls how many bits of the
     * DTM node identifier numbers are used to identify a node within a
     * document, and thus sets the maximum number of nodes per
     * document. The remaining bits are used to identify the DTM
     * document which contains this node.
     * <p>
     * If you change IDENT_DTM_NODE_BITS, be sure to rebuild _ALL_ the
     * files which use it... including the IDKey testcases.
     * <p>
     * (FuncGenerateKey currently uses the node identifier directly and
     * thus is affected when this changes. The IDKEY results will still be
     * _correct_ (presuming no other breakage), but simple equality
     * comparison against the previous "golden" files will probably
     * complain.)
     */
    public static final int IDENT_DTM_NODE_BITS = 16;


    /**
     * When this bitmask is ANDed with a DTM node handle number, the result
     * is the low bits of the node's index number within that DTM. To obtain
     * the high bits, add the DTM ID portion's offset as assigned in the DTM
     * Manager.
     */
    public static final int IDENT_NODE_DEFAULT = (1 << IDENT_DTM_NODE_BITS) - 1;


    /**
     * When this bitmask is ANDed with a DTM node handle number, the result
     * is the DTM's document identity number.
     */
    public static final int IDENT_DTM_DEFAULT = ~IDENT_NODE_DEFAULT;

    /**
     * This is the maximum number of DTMs available.  The highest DTM is
     * one less than this.
     */
    public static final int IDENT_MAX_DTMS = (IDENT_DTM_DEFAULT >>> IDENT_DTM_NODE_BITS) + 1;


    /**
     * %TBD% Doc
     * <p>
     * NEEDSDOC @param dtm
     * <p>
     * NEEDSDOC ($objectName$) @return
     */
    public abstract int getDTMIdentity(DTM dtm);

    /**
     * %TBD% Doc
     * <p>
     * NEEDSDOC ($objectName$) @return
     */
    public int getDTMIdentityMask() {
        return IDENT_DTM_DEFAULT;
    }

    /**
     * %TBD% Doc
     * <p>
     * NEEDSDOC ($objectName$) @return
     */
    public int getNodeIdentityMask() {
        return IDENT_NODE_DEFAULT;
    }
}
